Chapter 7 - Metals - Oral Questions

Question 1

How do you work harden a piece of metal?

Answer 1

By cold working the metal

Question 2

Describe the primary difference between a thermosetting and thermoplastic resin

Answer 2

A thermosetting resin doesn’t soften when heated and chars or burns rather than melting.

Thermoplastic resins become soft and pliable when heated, and harden when cooled

Question 3

Explain how thermoplastic and thermosetting resins are commonly used in modern aircraft

Answer 3

Plexiglas is a thermoplastic resin used for windshields and windows.

Thermosetting resins are most often used as the matrix material in composite structures

Question 4

Name one of the types of resin commonly used as matrix material for aircraft composite laminates

Answer 4

Polyester resin or

Epoxy resin

Question 5

What are some of the materials that are commonly used as the reinforcing component in a composite structure?

Answer 5

Fiberglass,

Aramid (Kevlar),

Graphite (carbon) fiber,

linen, and

paper

Question 6

What are the reasons that alloy steel that is responsive to heat treatment is usually less suitable for welding?

Answer 6

It may become brittle and lose its ductility in the area of the weld

Question 7

Give one advantage of pre-preg materials, other than saving time in the construction or repair of composite components

Answer 7

1) Pre-preg fabrics contain the correct amount of matrix.
2) The matrix material evenly and completely permeates the reinforcing fibers.
3) The matrix has the resin and hardener in the correct proportions